Railway signal control system



Oct. 23, 1951 H. s. YOUNG RAILWAY SIGNAL CONTROL SYSTEM a w% L" Q 3%, R

INVENTOR. 5. Huang.

HA5 Ara 02m 3v 4 1 N l Filed Aug. 19, 1947 Paten tecl Oct. 23, 1951RAILWAY SIGNAL CONTROL SYSTEM Henry S. Young, Wilkinsburg, Pa., assignorto Westinghouse Air Brake Company, a corpora tion of PennsylvaniaApplication August 19, 1947, Serial No. 769,479

nals each of which comprises a lamp and a mechanism operated by powerfrom primary batteries, it is desirable to energize the signal lamps andmechanisms for minimum periods of time, in order to conserve the primarybatteries. It is also desirable to accomplish this result by a signalcontrol system embodying a minimum number of line control conductors, inorder to conserve line material.

One feature of my invention is the provision of an arrangement in whichthe track relays are the only parts of the apparatus of a railway signalcontrol system which 7 are normally energized. All other control relaysin the system, and the signal operating mechanisms or elements and lampsare normally deenergized, and become energized only in response to theapproach of a train. With this invention, only two line controlconductors are required between the consecutive signals.

Another feature of my invention is the provision of a control circuitfor a pole-changerrelay which includes its control winding and a signaloperating element for an associated signal, and also the control windingof an approach relay for the next signal in advance, all in series, whenthe block for its signal and also the first block in the rear of itssignal are unoccupied while a portion of the second block in the rear ofits signal is occupied, and the provision of a. signal operating circuitwhich includes a signal operating element in series with only thecontrol winding of the approach relay for the next signal in advancewhen the block for its signal is clear and the first block in the rearis occupied.

The parts are so proportioned that only the pole-changer relay isoperated byits control circuit, the current flowing in this circuitbeing of insuflicient magnitude to operate the signal mechanism and theapproach relay in series with the pole-changer relay. The approachrelay, as well as the signal mechanism, is operated by the signaloperating circuit.

I shall describe two forms of apparatus embodying my invention, andshall then point out the novel features thereof in claims.

In the accompanying drawings, Fig. 1 is a diagrammatic view showing oneform of apparatus embodying my invention, in which the track relays arenormally energized but all other relays and the signal mechanisms andlamps are nor- 14 Claims. (01. 246-46) mally deenergized, and in whicheach signal mechanism becomes energized in series with the controlwinding of an approach relay for the next signal in advance when a trackrelay for the next block in the rear becomes deenergized by a train, andthe approach relay for the next signal in advance, upon becomin thusenergized, completes a circuit for energizing a pole-changer relay forthe next signal in advance, and this pole-changer relay then operatesmake-beforebreak contacts for controlling the circuit already closed forthe associated approach relay and the mechanism of the signal in therear; and Fig. 2 is a diagrammatic view showing a modification of theapparatus of Fig. 1, in which each approach relay is made slow releasingby a half-wave rectifier connected across its winding, and thepolechanger relays are provided with standard contacts instead ofmake-before-break contacts.

Similar reference characters refer to similar parts in each of theviews.

In each of the views, contacts operated by the various relays areidentified by numbers, such numbers having distinguishing prefixes fromwhich they are separated by a. dash when the contacts are shown apartfrom the relay by which they are operated. The prefix for each of thesecontact numbers comprises the reference character for the respectiverelay by which the contact is operated. For example, contact A4R-6,shown in the circuit for mechanism M of signal 48 in Fig; l, isidentified by the number 6 separated by a dash from the prefix A4R whichis the reference character for relay A4R by which this contact isoperated.

Referring further to Fig. 1, a stretch of railway track is showndesignated by the reference character ET. Trafiic movements over trackET are made in the direction indicated by the arrow, toward the right,as shown in the drawing, which I shall assume is the eastbounddirection.

Rails I and la of track ET are divided by insulated joints 2 into blockssuch as bd and d Each block is further divided by other insulated joints2 into sections such as 12-0 and cd of block bd. Sections 11-?) and f-gof two other blocks are also shown, one at each end of the drawing. 7

Signals, designated by the reference characters 48, BS and 8S, are shownadjacent the entering ends b, d and respectively, of the various blocks.These signals may be of any suitable design, such, for example, as thewell-known searchlight type. Each signal comprises a lamp 2' and anoperating element or mechanism M.

Each track section is provided with a track circuit including a suitablesource of current such, for example, asa battery 3 connected across therails adjacent one end of the section, and a track relay, designated bythe reference character R with a distinguishing numeral prefix whichcomprises the numerical prefix for the reference character for thesignal for its block, connected across the rails adjacent the oppositeend of the section.

Associated with each signal are an approach relay and a pole-changerrelay. Each approach relay is designated by the reference character Awith a numerical prefix which is the same as that in the referencecharacter for its signal. Each pole-changer relay is designated by thereference character P with 'a numerical prefix which is the same as thatin the reference character for its signal.

Each pole-changer relay is equipped with pole changer contacts of thewell-known make-before-break or continuity type. A contact of this type,when its control relay becomes energized, closes at its front pointbefore it opens at its back point. Similarly, when its control relaybecomes deenergized, a contact of this type closes at its back pointbefore it opens at its front point.

Y'Each signal lamp i is controlled by a back contact of a track relayfor the next track section to the rear of its signal. Each signalmechanism M'is provided with an operating circuit which is controlled inpart by a back contact of the same track relay which controls its lamp.Each signal operating circuit includes, in series with its signalmechanism M, the control winding of the approach relay for the nextsignal in ad- Vance. The parts o'f'the apparatus are so proportionedthat, whenever a signal mechanism M is operated by its operatingcircuit, the approach relay for the next signal in advance will also beoperated by the same -'circuit.

Each approach relay, upon becoming operated, completes a control circuitfor the pole-changer relay for the same signal if the block for itssignal and also the next block in the rear are unoccupied. The controlcircuit for each polechanger relay includes its control winding and the-'operating element or mechanism M for its signal, and also the :controlwinding :for the approachrelay for the next signal in advance. The partsof the apparaus are so proportioned that only the pole-changer relayoperated by this circuit and the signal mechanism M and the approachre'lay do :not respond.

Referring now to Fig. 2, the apparatus of Fig. 1 is "here modified sothat each approach relay is :made slow releasing by some suitable meanssuch, "for example, asa half-wave rectifier F connectedin multiple withthe winding of each approach relay, as shown for relay (in, and thepole-changer contacts of the pole-changer relay are of the usualstandard type and not of the make-before-break type, as shown for relay6P.

Having described, in'general, the arrangement of the various .parts ofapparatus embodying my invention, I shall now describe the circuits andoperation in detail.

As shown in Fig. l, a train, designated by the reference character W, ison section a,-b, and track relay A2R is therefore deenergized. Beforethe arrival of train W on section (bb, all the track relays wereenergized, but all other parts of the apparatus, including the approachrelays A and the pole-changer relays P, and also the signal mechanisms Mand lamps i were deenergized.

When train W entered section a--b, lamp i of signal 48 became lighted,as shown in Fig. '1, by itscircuit passing from terminal B of a suitablesource of current, through contact 4 of iii relay A2R, and lamp i toterminal N of the same source of current. At the same time, a circuitwas completed, including the winding of relay 6A in series withmechanism M of signal 46, by which mechanism M was energized by currentof reverse polarity, this circuit passing from terminal B, through thewinding of relay 6A, back point of contact I0 of relay 8P, mechanism M,back point of contact 8 of relay AZR, contact 1 of relay 4R, contactA4R-6, and the back point of contact 5 of relay GP to terminal N.

Relay 6A, upon becoming energized by this circuit, completed a circuitfor energizing relay GP in series with mechanism M of signal 6S and thewinding of relay 8A for signal 88, this circuit passing from terminal B,through the winding of relay 8A, back point of contact 18 of relay 8P,mechanism *M of signal 88, winding of relay 6P, contact 9 of relay BA,front point of contact 8 of relay AflR, contact I of relay GR, contactAfiR-G, and the back point of contact 5 of relay 8P to terminal N. Thevarious parts of the apparatus being so proportioned that only relay 6Presponds to 'energization by this circuit for moving its contacts fromtheir back points to their front points, mechanism M does not move, andtherefore remains in the stop position, and relay BA doesnot close itsfront contacts.

Because contacts 5 and H) of relay 6P are of the make-before-break type,relay 6A is continuously energized while contacts 5 and 10 of relay 6?are moving from their back to their front points. One of the twocircuits by which relay 6A is energized during this transfer period ofcontacts 5 and ill passes from terminal B, through the winding of relay6A, front point of contacti, and back point of contact -5, to terminalN. When contacts 5 and H! of relay 6P become closed at their frontpoints and open at their back points, mechanism M of signal 45 becomesenergized by current of normal polarity, so that mechanism M of signal43 moves from the caution to the proceed position, shown in the drawing.

When train W enters section b-c, relay 4R becomes deenergized, andtherefore its contact 1 opens the circuit previously traced for relay 6Aand mechanism M of signal 48, causing mechanism M to move to the stopposition and relay 6A to open its contact 9 in the circuit previouslytraced for relay 6?, which causes relay 6P to be deenergized.

When train W leaves section a-b, .relay A2R becomes energized and opensits contact 4, therebyextinguishing lamp 2 of signaldS. At the sametime, relay AZR moves its contact 8 from its back point to its frontpoint.

When :train D enters section c-d, relay .A4R becomes deenergized-,.andthereupon completes a circuit ,for lighting lamp 1' of signal (is, whichis similar to .the circuit previously traced for lamp 1 of signal 48when train W entered section ab. At the same time, mechanism M of signalBS becomes energized by current of reverse polarity in series with thewinding of relay 8A, causing the mechanism M of signal ES to move to thecaution position. Relay :8-A,- upon1becoming energized, completes acircuit :for energizing relay 8B, which then causes mechanism M ofsignal 88 to be energized by current of'normalpolarity a nd to'move tothe proceed position.

:As .train'W proceeds further, each consecutive signal will becontrolled so that its lamp 1' will become lighted and its mechanism Mwill be moved from 'thestop to the-caution position and then to theproceed position, as described for signals 4S and 6S.

Although I have herein shown and described only two forms of apparatusembodyin my invention, it is understood that various changes andmodifications may be made therein within the scope of the appendedclaims without departing from the spirit and scope of my invention.

Having thus described my invention, What I claim is:

1. In a railway signal control system for a stretch of railway trackwhich is divided into a plurality of consecutive blocks each of which isprovided with a signal having an operating element for governing trafilcmovements in a given direction through its block, the combinationcomprising a pole-changing rela and an approach relay for each of saidsignals so proportioned that if a circuit is completed including thewinding of one of said approach relays in series with one of said signaloperatin elements the approach relay will close a front contactand saidone signal operating element will be operated for displaying a cautionor a proceed indication but that if a circuit is completed including thewinding of one of said pole-changing relays and one of said signaloperating elements and also the winding of one of said approach relaysall in series the polechanging relay will close its front contacts butthe approach relay and the signal operating element will not beoperated, a signal control circuit for each of said signals includingits operating element in series with the winding of the approach relayfor the next signal in advance and controlled by the pole-changing relayfor the next for its signal and the winding of the approach relay forthe next signal in advance all in series and controlled by frontcontacts of the approach rela for its signal and of said track relay forthe next block in the rear.

2. In a railway signal control system for a stretch of railway trackwhich is divided into a plurality of consecutive blocks each of which isprovided with a signal having an operating element for governing trafiicmovements in a' given direction through its block, the combinationcomprising, a pole-changing rela and an approach relay for each of saidsignals, means controlled by traflic conditions in each of said blocksand by a front contact of the approach relay for the signal for the sameblock for energizing the pole-changing relay for its signal if the blockis unoccupied, and a signal control circuit for each of said signalsincluding its operating element in series with the winding of theapproach relay for the next signal in advance and controlled bymake-before-break pole-changing contacts of the pole-changing relay forthe next signal in advance.

3. In a railway signal control system for a stretch of railway'trackwhich is divided into a plurality of consecutive blocks each of which isprovided with a signal having an operating element for governing traflicmovements in a given direction through its block, the combinationcomprising, a pole-changing relay for each of said signals, and anenergizing circuit for each of said pole-changing relays including itscontrol winding in series with the operating element for its signal andcontrolled by trafiic conditions in the block for its signal andincluding contact means controlled by the pole-changing relay for theplurality of consecutive blocks each of which is.

provided with a signal having an operating element for governing trafiicmovements in a given direction through its block, the combinationcomprising, a pole-changing relay for each of said signals, a signalcontrol circuit for each of said signals including its operating elementand controlled by a back contact of a track relay for the next block inthe rear and by the pole-changing relay for the next signal in advance,and an energizing circuit for each of said pole-changing relayscontrolled by trafiic conditions in the block for its signal and by afront contact of said track relay for the next block in the rear.

5. In a railway signal control system for a stretch of railway trackwhich is divided into a plurality of consecutive blocks each of which isprovided with a, track circuit including a track relay and with a signalhaving an operating element for governing traffic movements in a givendirection through its block, the combination comprising, a pole-changingrelay and an approach relay for each of said signals, an energizingcircuit for each of said pole-changing relays including its controlwinding in series with the operating element for its signal andcontrolled by a front contact of its approach relay, and an. energizingcircuit for each of said signals including its operating element inseries with the control winding of the approach relay for the nextsignal in advance and controlled by polechanging contacts of thepole-changing relay for the next signal in advance.

6. In a railway signal control system for a stretch of railway trackwhich is divided into a plurality of consecutive blocks each of which isprovided with a track circuit including a track relay and with a signalhaving an operating element for governing trafilc movements in a givendirection through its block, the combination comprising, a pole-changingrelay for each of said signals, an energizing circuit for each of saidpole-changing relays including its control winding in series with theoperating element for its signal and controlled by a front contact ofthe track relay for the next block in the rear, and

an energizing circuit for each of said signals including its operatingelement controlled by a back contact of the track relay for the nextblock in the' rear and by the pole-changing relay for prising, apole-changing relay and an approach a back contact of said track relayfor the next block in the rear.

8. In a railway signal control system for a stretch of railway trackwhich is divided into a plurality of consecutive blocks each of which isprovided with a track circuit including a track relay and with a signalhaving an operating element for governing trafiic movements in a givendirection through its block, the combination comprising, a pole-changingrelay and a slow release approach relay for each of said signals, anenergizing circuit for each of said pole-charging relays controlled bytraffic conditions in the block for its signal and by a front contact ofthe approach relay for its signal, and an energizing circuit for each ofsaid signals including its operating element and the control winding ofthe approach relay for the next signal in advance and controlled bypole-changing contacts of the pole-changing relay for the next signal inadvance.

9. In a railway signal control system for stretch of railway track whichis divided into a plurality of consecutive blocks each of which isprovided with a track circuit including a track relay and with a signalhaving an operating element and a lamp for governing traihc movements ina given direction through its block, the combination comprising, anapproach relay and a pole-changing relay for each of said signals, andenergizing circuits for said approach and pole-changing relays and alsofor said signal lamps and operating elements which are normally open butwhich are closed by said track relays in response to a train moving oversaid stretch of track.

10. In a railway signal control system for a stretch of railway trackwhich is divided into a plurality of consecutive blocks each of which isprovided with a track circuit including a track pole-changing relay foreach of said signals, i

means controlled by said track relay for each of said blocks when saidtrack relay becomes deenergized by a train for operating the signaloperating element for the next signal in advance and lighting its lampand for operating the approach relay for the second signal in advance,means including a front contact of each of said approach relays forenergizing the pole changing relay for its signal, and means controlledby each of said pole-changing relays for controlling the polarity of thecurrent for operating the signal operating element for the next signalin the rear.

11. In a railway signal control system for a stretch of railway track wich is divided into a plurality of consecutive blocks each of which isprovided with a track circuit including a track relay and with a signalhaving an operating element for governing traffic movements in a givendirection through its block, the combination comprising, a pole-changingrelay and an approach relay for each of said signals, and meanscontrolled by said track relay for each of said blocks when said trackrelay becomes deenergized by a train for operating the signal operatingelement for the first signal in advance by current of normal polarity inseries with the winding of the approach relay for the second signal inadvance and for operating the polechanging relay associated with thesecond signal in advance by current of reverse polarity in :serice withthe operating element for the second signal in advance and also inseries with the "control winding of the approach relay for the thirdsignal in advance but of insufficient magnitude for operating either theoperating element :for the second signal in advance or the approachrelay for the third signal in advance. a 12. In a railway signal controlsystem for stretch of railway track which is divided into a plurality ofconsecutive blocks each of which is provided with a track circuitincluding a track relay and with a signal having an operating elementfor governing trafi'ic movements in a given direction through its block,the combination comprising, a pole-changing relay and an approach relayfor each of said signals, and means controlled by said track relay foreach of said blocks when said track relay becomes deenergized by a trainfor energizing the signal operating element for the first signal inadvance in series with the control winding of the approach relay for thesecond signal in advance by current of sufficient magnitude to operateboth of them and for energizing the control winding of the pole-changingrelay for the second signal in advance and the signal operating elementfor the second signal in advance and also the control winding of theapproach relay for the third signal in advance all in series by currentof suiiicient magnitude to operate only the pole-changing relay for thesecond signal in advance.

13. In a railway signal control system for a stretch of railway trackwhich is divided into a plurality of consecutive blocks each of which isprovided with a track circuit including a track relay and with a signalhaving an operating element and a lamp for governing trafiic movementsin a given direction through its block, the combination comprising,normally deenergized control means and operating circuits for saidsignal operating elements controlled by said track relays and includingonly two line control conductors between the consecutive signals forefieoting energization of said control means and operating circuits inresponse to an approaching train,

14. In a railway signal control system for a stretch of railway trackwhich is divided into-a first and a second section and provided with afirst and a second signal each having an operating element for governingtraffic movements through said first and second sections respectively,the combination comprising, a polechanger relay, means responsive totrafiic conditions for energizing said pole-changer relay in series withthe operating element of said second signal by current which is ofinsufficient magnitude to operate said second signal only if both saidsections are unoccupied, and pole changing contacts operated by saidpole-changer relay for controlling said first signal to display acaution indication when said pole-changer relay is deenergized and todisplay a proceed indication when said pole-changer relay is energized.

HENRY S. YOUNG.

REFERENCES CITED The following references are of record in the idle ofthis patent:

UNITED STATES PATENTS Numoer Name Date 1,790,524 Spray Jan. 27, 19312,017,452 Young Oct. 15, 1935 2,115,459 Gilbert Apr. 26, 1938

